Methods and apparatus for processing substrates using an ion shield

ABSTRACT

Methods and apparatus for processing a substrate are provided. In some embodiments, a method of processing a substrate having a first layer may include disposing a substrate atop a substrate support in a lower processing volume of a process chamber beneath an ion shield having a bias power applied thereto, the ion shield comprising a substantially flat member supported parallel to the substrate support, and a plurality of apertures formed through the flat member, wherein the ratio of the aperture diameter to the thickness flat member ranges from about 10:1-1:10; flowing a process gas into an upper processing volume above the ion shield; forming a plasma from the process gas within the upper processing volume; treating the first layer with neutral radicals that pass through the ion shield; and heating the substrate to a temperature of up to about 550 degrees Celsius while treating the first layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. provisional patent applicationSer. No. 61/711,495, filed Oct. 9, 2012, which is herein incorporated byreference.

FIELD

Embodiments of the present invention generally relate to semiconductorprocessing equipment.

BACKGROUND

The inventors have observed that nitridation of 3D device structurescannot be easily performed using typical plasma ion exposure due to thenon-conformal nature of the plasma sheath, which prevents conformaldoping of the top surface of a film and the device sidewall. Instead,the inventors believe that 3D conformal nitridation requires radical orneutral species driven reactions. One method of nitridizing a hafniumoxide based 3D high-k gate stack is through the use of an inductivelycoupled plasma generated using ammonia and, optionally, an inert gas,and/or nitrogen gas (N₂). However, the inventors have observed that thisprocess also leads to the formation of a number of reactive hydrogenspecies, including both hydrogen radicals and hydrogen ions. Thesereactive hydrogen species can potentially penetrate the nitridized filmand negatively interact with the gate stack materials. Additionally, theinventors have observed that this process also leads to the formation ofa number of inert gas and/or nitrogen ions, which also undesirablycontribute to the non-conformal processing results. The inventorspropose that reducing or eliminating the reactive hydrogen species priorto their penetration and interaction with the gate stack materials canprevent device failure, and reducing or eliminating the inert gas and/orions prior to their interaction with the substrate can enhance conformalprocessing results.

As such, the inventors have provided improved methods and apparatus fornitridizing materials, such as those in 3D device structures.

SUMMARY

Methods and apparatus for processing a substrate are provided herein. Insome embodiments, such processing includes nitridizing a substrate. Insome embodiments, a method of processing a substrate having a firstlayer disposed thereon, for example that is part of a 3D device disposedon or being fabricated on the substrate, may include disposing asubstrate atop a substrate support disposed in a lower processing volumeof a process chamber beneath an ion shield having a bias power appliedthereto, wherein the ion shield comprises a substantially flat membersupported parallel to the substrate support, and a plurality ofapertures formed through the flat member, and wherein the ratio of thediameter of the apertures to the thickness of the flat member has arange of about 10:1 to about 1:10; flowing a process gas into an upperprocessing volume above the ion shield; forming a plasma from theprocess gas within the upper processing volume; treating the first layerwith neutral radicals that pass through the ion shield; and heating thesubstrate to a temperature of up to about 550 degrees Celsius whiletreating the first layer.

In some embodiments, a substrate processing apparatus may include achamber body defining a processing volume having an upper processingvolume and a lower processing volume; a substrate support disposedwithin the lower processing volume; an ion shield disposed in theprocessing volume and dividing the processing volume into the upperprocessing volume and the lower processing volume, the ion shieldcomprising a substantially flat member supported parallel to thesubstrate support, and having a plurality of apertures formed throughthe substantially flat member, wherein the ratio of the diameter of theapertures to the thickness of the substantially flat member has a rangeof about 10:1 to about 1:10; a biasing power source coupled to the ionshield; a shield support disposed within the processing volumeconfigured to support the ion shield above the substrate support in asubstantially parallel orientation with respect to the substrate; a heatsource to provide heat energy to a substrate when disposed on thesubstrate support; and an RF power source for forming a plasma withinthe upper processing volume.

Other and further embodiments of the present invention are describedbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention, briefly summarized above anddiscussed in greater detail below, can be understood by reference to theillustrative embodiments of the invention depicted in the appendeddrawings. It is to be noted, however, that the appended drawingsillustrate only typical embodiments of this invention and are thereforenot to be considered limiting of its scope, for the invention may admitto other equally effective embodiments.

FIG. 1 depicts a flow chart for a method of processing a substrate inaccordance with some embodiments of the present invention.

FIGS. 2A-2B depict a schematic view of a substrate processing chamber inaccordance with some embodiments of the present invention.

FIG. 3 depicts a partial perspective view of an ion shield in accordancewith some embodiments of the present invention.

FIGS. 4A-4C depict stages of fabrication of a nitridized layer atop asubstrate in accordance with some embodiments of the present invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. The figures are not drawn to scale and may be simplifiedfor clarity. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

Embodiments of the present invention provide improved methods andapparatus for processing a substrate. Embodiments of the presentinvention may advantageously allow for the conformal nitridation of 3Dstructures, such as high-k materials used in 3D structures, by reducingthe impact of reactive species, such as hydrogen radicals and hydrogenions, as well as other ions, resulting from an inductively coupledplasma formed from an ammonia source. The methods and apparatus may alsobe used to nitridize other materials in other applications includingthose not having 3D structures.

FIGS. 2A and 2B depict particular embodiments of a process chamber 200for processing substrates in accordance with some embodiments of thepresent invention. The process chamber 200 is depicted for illustrativepurposes and should not be used to limit the scope of the invention. Inthe depicted embodiment, the process chamber 200 has a substantiallyflat dielectric ceiling 212. However, other modifications of the processchamber 200 may have other types of ceilings, for example, a dome-shapedceiling.

The process chamber 200 depicted in FIGS. 2A and 2B generally comprisesa substrate support 202 and a slit valve 224 within a chamber body 204.The slit valve 224 allows the ingress and egress of a substrate 206 toand from the substrate support 202. The substrate support 202 has anupper surface to support the substrate 206 such that a first layer 230of the substrate 206 is positioned for processing. In some embodiments,the process chamber 200 further comprises a heat source 240 to heat thesubstrate 206 to a desired temperature. The heat source 240 may be anytype of heat source suitable to provide control over the substratetemperature, for example a resistive heater coupled to the substratesupport 202 or heat lamps (not shown) disposed in a position to provideheat energy to the surface of the substrate 206 either directly orthrough some other component. For example, in some embodiments, the heatsource 240 is the resistive heater disposed within an electrostaticchuck, which advantageously enhances temperature control of thesubstrate due to enhanced thermal contact between the substrate and theelectrostatic chuck due to the clamping force provided by theelectrostatic chuck.

The chamber body 204 defines a processing volume 208 divided into anupper processing volume 234 and a lower processing volume 236 by an ionshield 210 disposed within the processing volume 208. The upperprocessing volume 234 is disposed above the ion shield 210 and the lowerprocessing volume 236 is disposed below the ion shield 210. The upperprocessing volume 234 and the lower processing volume 236 are fluidlycoupled by openings in the ion shield 210.

A process gas source 222 is coupled to the process chamber 200 to supplya process gas to the upper processing volume 234. In some embodiments,the process gas is a nitrogen containing gas, for example ammonia (NH₃),alone or in combination with an inert gas, such as argon (Ar) or thelike, which is suitable for a nitridation process. In some embodiments,the process gas is an oxygen containing gas, such as oxygen (O₂),suitable for an oxidation process. In some embodiments, the process gasis a halogen containing gas, such as chlorine (Cl₂), fluorine (F₂),bromine (Br₂), nitrogen trifluoride (NF₃), trifluoromethane (CHF₃),hydrogen chloride (HCl), hydrogen bromide (HBr), or the like, suitablefor an etch process.

A plasma can be formed in the upper processing volume 234 from theprocess gas by applying RF power from a plasma power source 216. Theplasma power source 216 can be coupled to an electrode disposed in ornear the ceiling 212 of the process chamber suitable to couple RF powerto the process gases disposed in the process chamber. For example, theplasma power source 216 and the electrode can be configured to form acapacitively coupled plasma, and inductively coupled plasma, or thelike.

The plasma may form reactive species, such as in a nitridation processwhere the plasma can form hydrogen radicals and hydrogen ions, as wellas nitrogen and/or inert gas ions, in addition to the other componentsof the plasma. These reactive hydrogen species can potentially penetratethe nitridized film and negatively interact with the substrate ormaterials disposed on the substrate. In addition, inert or nitrogen gasions can also negatively impact conformal reactions or processing ofthree-dimensional structures on the substrate. The ion shield 210advantageously controls the spatial distribution of the reactive andneutral species in the process chamber 200 during nitridation, or other,processes. Specifically, the ion shield 210 substantially prevents thereactive hydrogen species and other ions from reaching the substrate 206in the lower process volume 236. Moreover, the ion shield 210 allowsspecies with high surface recombination rates, such as hydrogenradicals, to recombine preferentially on the surface of the ion shield210, leaving a higher relative concentration of desirable species (forexample, nitrogen-containing species in a nitridation process) to reachthe surface of the substrate 206.

In some embodiments, the ion shield 210 is coupled to a bias powersource 220 which advantageously allows for the selective biasing of theion shield 210 to enhance ion screening (e.g., reduction of chargedradicals and ions) during the nitridation process. The bias power sourcecan be a DC power source or an RF power source. For example, a negativevoltage applied to the ion shield 210 can enhance the screening ofpositive ions by attracting the positive ions to the surface of the ionshield 210. The ion shield 210 is made of a conductive material such asaluminum, anodized aluminum, aluminum oxide, or quartz. In someembodiments, the ion shield 210 is electrically isolated from thechamber body 204 and the substrate support 202. In some embodiments, theion shield 210 is grounded, for example by electrically coupling to thechamber body 204 and/or the substrate support 202. The choice ofmaterial used for the ion shield 210 can be selected to contribute tothe control of the recombination rate at the surface of the ion shield210. For example, hydrogen radicals recombine more readily on analuminum surface than on a quartz surface.

The ion shield 210 is supported above the substrate support 202 by asupport element. In some embodiments, the height at which the ion shield210 is supported may vary in order to control the process within theprocess chamber 200. For example, in an etch process, a faster etch ratemay be obtained by locating the ion shield 210 closer to the substratesupport 202 and, therefore, the substrate 206. Alternatively, a lower,but more controlled, etch rate may be obtained by locating the ionshield 210 farther from substrate support 202. In some embodiments, theheight of the ion shield 210 may range from about 0.5 inches (3.81 cm)to about 5.5 inches (10.16 cm) in a process chamber 200 having adistance of about 6 inches (15.24 cm) between the substrate 206 and theceiling 212. In some embodiments, the ion shield 210 is supported abovethe substrate support 202 at distance of about 2 to about 4 inches abovethe substrate 206 in a process chamber having a substrate to ceilingdistance of about 6 inches. Other support heights may be used inchambers having other configurations.

The ion shield 210 is supported using any suitable structure in a mannerthat maintains the ion shield 210 in a substantially parallelorientation with respect to the substrate 206 or the substrate support202. In some embodiments, the shield support element 238 is a ledge 242,as depicted in FIG. 2A, attached to the chamber wall 204 (or to aprocess cavity liner disposed along the chamber wall) and supporting theion shield 210 above the substrate support 202. In some embodiments asshown in FIG. 2B, the shield support element 238 is a stand 244 coupledto a bottom of the process chamber 200 and located around an outerperimeter of the substrate support 202, or a stand 244 having a liftmechanism 246 (e.g., an actuator, a motor, combinations thereof, or thelike) to raise and lower the ion shield 210, or any other suitablestructure within the process chamber 200.

For example, in some embodiments, a lift mechanism 246 may be coupled tothe ion shield 210 to control the position of the ion shield 210 withrespect to the substrate support 202, for example over a range extendingabove and below the slit valve 224. The lift mechanism 246 can supportthe ion shield 210 (e.g., the lift mechanism can be the support element)or the lift mechanism 246 can move the ion shield 210 from resting onthe support element to a position disposed above the support element(such as the ledge 242 shown in FIG. 2A). The lift mechanism 246 canraise the ion shield 210 from a first position above the substrate 206,but below the slit valve 224, to a second position above the slit valve224 to allow the substrate 226 to enter and exit the processing chamber200 from the slit valve 224. In some embodiments, the lift mechanism 246is generally located around an outer perimeter of the substrate support202. An upper end of the lift mechanism 246 may be press fit into acorresponding hole formed in the ion shield 210. Alternatively, theupper end of the lift mechanism 246 may be threaded into the ion shield210 or into a bracket secured to an underside of the ion shield 210.Other fastening methods not inconsistent with processing conditions mayalso be used to secure the lift mechanism 246 to the ion shield 210.

In some embodiments, the support element for the ion shield 210 is madeof conductive material. In some embodiments, the support element isanodized. In some embodiments, the support element is not conductive butis connected to a ground path. In some embodiments, the ion shield 210may be part of an easily-replaceable process kit for ease of use,maintenance, replacement, and the like. It is contemplated that the ionshield 210 may be configured to be easily retrofitted in existingprocess chambers.

FIG. 3 depicts a perspective view of one specific embodiment of the ionshield 210. In some embodiments, the ion shield 210 comprises one ormore substantially flat members 214 supported parallel to the substratesupport 202 and a plurality of apertures 218 formed through the one ormore flat members 214. In some embodiments, multiple flat members 214having apertures 218 are stacked together in order to manipulate thequantity of ions that pass from a plasma formed in an upper processingvolume 234 of the process chamber 200 to a lower processing volume 236located between the ion shield 210 and the substrate 206. In someembodiments, the flat member 214, could comprise a plate, a screen amesh, or a combination thereof.

The plurality of apertures 218 may vary in size, spacing and geometricarrangement across the surface of the plate 214. The plurality ofapertures 218 control the quantity of ions that pass from a plasmaformed in the upper processing volume 234 of the process chamber 200 tothe lower processing volume 236 located between the ion shield 210 andthe substrate 206. As such, the size and quantity of the apertures 218affects the ion density in the lower processing volume 236. For example,the ion density may be substantially lowered, such that processing ispredominantly provided by neutral radical species of the plasma.

The size of the apertures 218 generally range from about 0.03 inches(0.07 cm) to about 3 inches (7.62 cm), or from about 0.125 inches toabout 1 inch. The apertures 218 may be arranged to define an open areain the surface of the plate 214 of from about 2 percent to about 90percent. In one embodiment, the one or more apertures 218 includes aplurality of approximately half-inch (1.25 cm) diameter holes arrangedin a square grid pattern defining an open area of about 30 percent. Itis contemplated that the holes may be arranged in other geometric orrandom patterns utilizing other size holes or holes of various sizes.

In some embodiments, the size, shape and/or patterning of the holes mayvary depending upon the desired ion density in the lower processingvolume 236. For example, in some embodiments, a similar hole size may beprovided in a geometric pattern having regions of relatively higher andlower numbers of holes to control the concentration of radicals inregions corresponding to the geometric pattern without altering theoverall composition of the species reaching the substrate.

In some embodiments, the size, shape and patterning of the holes mayvary depending upon the desired ion density in the lower processingvolume 236. For example, more holes of small diameter may be used toincrease the radical to ion density ratio in the lower processing volume236. In other situations, a number of larger holes may be interspersedwith small holes to increase the ion to radical density ratio in thelower processing volume 236. Alternatively, the larger holes may bepositioned in specific areas of the plate 214 to contour the iondistribution in the lower processing volume 236.

In combination with the size of the apertures 218, the thickness of theone or more substantially flat members 214 may be selected to controlthe length of each aperture 218. The aspect ratio (i.e. the ratio of thediameter of the apertures 218 to the thickness of the one or moresubstantially flat members 214) of the ion shield 210 controls the iondensity within the lower processing region 236. In some embodiments, theaspect ratio ranges from about 10:1 to about 1:10. In some embodiments,the aspect ratio ranges from about 2:1 to about 1:2.

FIG. 1 depicts one exemplary method 100 of processing a substrate usingthe processing chamber 200 described above. In some embodiments, atleast some portions of the method 100 may be performed in a substrateprocessing chamber, for example, such as the chamber 200 described abovewith respect to FIGS. 2A and 2B (although other suitable processchambers may alternatively be used). Suitable process chambers that maybe adapted in accordance with the teachings disclosed herein include,for example, a Decoupled Plasma Nitridation (DPN) reactor, or a toroidalsource plasma immersion ion implantation reactor, such as the CONFORMA™chamber, each of which are available from Applied Materials, Inc. ofSanta Clara, Calif.

The method 100 is also described herein with respect to FIGS. 4A-4C,which depicts the stages of fabrication of a nitridized layer atop asubstrate in accordance with some embodiments of the present invention.The stages of fabrication of a nitridized layer are depicted forillustrative purposes and do not limit the scope of the invention. Forexample, in some embodiments, the method 100 may be used to oxidize oretch a substrate 206.

The method 100 begins at 102, where a substrate 206 is disposed atop asubstrate support 202 in a processing volume 208 of a process chamber200 and beneath an ion shield 210 disposed over the substrate support202.

The substrate 206 may have various dimensions, such as 200 mm, 300 mm,or other diameter wafers, as well as rectangular or square panels. Thesubstrate 206 may comprise a material such as crystalline silicon (e.g.,Si<100> or Si<111>), silicon oxide, strained silicon, silicon germanium,doped or undoped polysilicon, doped or undoped silicon wafers, patternedor non-patterned wafers, silicon on insulator (SOI), carbon dopedsilicon oxides, silicon nitride, doped silicon, germanium, galliumarsenide, glass, sapphire, or the like.

The substrate 206 includes a first layer 230 to be processed. The firstlayer 230 may be defined by a base material of the substrate 206 (e.g.,silicon) or by one or more layers disposed atop the base material. Forexample, the substrate 206 may include one or more completely orpartially fabricated semiconductor devices 400, as depicted in FIG. 4A.The semiconductor device 400 may be completely or partially formed uponthe substrate 206 and includes the first layer 230 to be processed, forexample nitridized. The semiconductor device (when completed) may be,for example, a field effect transistor (FET), dynamic random accessmemory (DRAM), a flash memory device, or a 3D device, such as a 3D logicdevice, or other 3D devices requiring 3D conformal processing, such asnitridation, oxidation, or etch, or the like.

The first layer 230 may be, for example, utilized as a gate dielectriclayer of a transistor device, a tunnel oxide layer in a flash memorydevice, a spacer layer atop a gate structure, an inter-poly dielectric(IPD) layer of a flash memory device, or the like. The first layer 230may have any thickness suitable in accordance with the particularapplication for which the first layer 230 may be utilized.

The first layer 230 may comprise an oxide layer, such as silicon oxide(SiO₂), a metal oxide, hafnium oxide (HfO₂), hafnium silicate(HfSiO_(x)), or any suitable oxide layer used in a semiconductor deviceand requiring nitridation. For example, in some embodiments, the oxidelayer may be a native oxide layer, or formed by any suitable oxidationprocess including the oxidation process discussed below. The first layer230 need not be limited to an oxide layer, and other suitable layers maybenefit from the inventive methods disclosed herein. For example, othersuitable embodiments of the first layer 230 may include othersilicon-containing layers such as SiC, or metal nitride layers, or thelike. The first layer 230 can also be a stack of layers, such as a firstsub-layer of SiO₂ and a second sub-layer of HfO₂ or a first sub-layer ofSiO₂ and a second sub-layer of HfSiO_(x), or the like.

The first layer 230 may be fabricated in one or more process chamberscoupled to a cluster tool that also has the process chamber 200 coupledthereto. One example of a suitable cluster tool is a Gate StackCENTURA®, available from Applied Materials, Inc., of Santa Clara, Calif.

Next, at 104, a process gas is flowed from a process gas source 222 intothe upper processing volume 234 above the ion shield 210. In someembodiments, the process gas is a nitrogen containing process gas, suchas ammonia (NH₃). The use of ammonia (NH₃) to form a plasmaadvantageously generates a thicker film atop the substrate 206 than aplasma formed using pure nitrogen. The nitrogen-containing process gasis provided at a flow rate of about 50 to about 1000 sccm, or from about100 to about 500 sccm. In some embodiments, an inert gas, such as argonor helium, is also provided into the process chamber along with thenitrogen-containing process gas. Diluting ammonia in an argon ambianceadvantageously enhances the dissociation of ammonia and, thus, increasesthe nitridation rate. The ammonium/argon process gas is provided at atotal flow rate of about 100 to about 2000 sccm, or about 200 to about1000 sccm. The ammonia may be about 1% to about 99%, or about 2.5 toabout 25%, of the process gas. In some embodiments, the process gas isan oxygen containing gas, such as oxygen (O₂), ozone (O₃), or water(H₂O) vapor, suitable for an oxidation process or a halogen containinggas, such as chlorine (Cl₂), fluorine (F₂), bromine (Br₂), nitrogentrifluoride (NF₃), trifluoromethane (CHF₃), hydrogen chloride (HCl),hydrogen bromide (HBr), or the like, suitable for an etch process.

Next, at 106 a plasma is formed in the process chamber 200 from thenitrogen-containing process gas by applying RF power from a plasma powersource (such as plasma power source 216) coupled to the process chamber200. The plasma is formed in the upper processing volume 234 of theprocess chamber 200. In some embodiments, RF power (continuous wave oreffective pulsed power) is provided in a range of about 50 to about 3000watts, or in some embodiments about 200 to about 1000 watts. RF powermay be pulsed at a duty cycle of about 2 to about 50%. The pressure inthe process chamber may range from about 2 mTorr to about 200 mTorr, orin some embodiments, about 10 to about 60 mTorr.

Optionally, at 108, a bias power of about 10 to about 2000 volts DCpower, or about 10 to about 2000 watts RF power, may be applied by abias power source 220 to the ion shield 210. Applying a bias power tothe ion shield 210 advantageously applies a voltage to the ion shield210 to enhance ion screening.

Next, at 110, which is depicted in FIG. 4B, the first layer 230 istreated using the neutral radicals 402 that pass through the ion shield210 to the lower processing volume 236. The neutral radicals 402 thatpass through the ion shield 210 are advantageously the dominant species,with little or no ions present. The inventors have discovered that ahigh ion concentration in the plasma results in a more vertical path forthe ions attracted to the substrate, which leads to poor conformality inapplications where top surfaces and sidewall surfaces need to beprocessed, such as in 3D devices, trenches, vias, or the like. Thus, theinventors have discovered that a reduced ion concentration in the plasmaimproves conformality in applications where top surfaces and sidewallsurfaces need to be processed, such as in 3D devices, trenches, vias, orthe like.

The inventors have further discovered that providing thermal energy, forexample by heating the substrate, enhances such radical driven conformalprocessing results. For example, in a nitridation process, as depictedin FIG. 4C, the neutral radicals 402 result in a conformally nitridizedfirst layer 404 atop the substrate 206. Alternatively, the substrate 206can be conformally oxidized using neutral radicals that pass through theion shield 210 by providing an oxygen-containing process gas. In someembodiments, the substrate 206 can be conformally etched using neutralradicals that pass through the ion shield 210 by providing an etchantspecies.

In some embodiments, the substrate 206 is heated while treating thefirst layer 230 using the neutral radicals 402 that pass through the ionshield 210. For example, the substrate 206 may be heated from about roomtemperature (about 30 degrees Celsius) to about 550 degrees Celsius, forexample from about 350 to about 450 degrees Celsius. The pressure insidethe process chamber 200 during nitridation is generally controlled atabout 2 mTorr to about 200 mTorr, or in some embodiments, about 10 toabout 60 mTorr. Although illustratively discussed above as treating thefirst layer 230 or forming a conformally nitridized first layer 404, theinventive methods disclosed herein can be used to advantageouslyconformally process substrates having three dimensional structuresformed in one or many layers.

Thus, methods of nitridizing materials on substrates and apparatus forperforming same have been disclosed herein. While the foregoing isdirected to embodiments of the present invention, other and furtherembodiments of the invention may be devised without departing from thebasic scope thereof.

The invention claimed is:
 1. A method of processing a substrate having afirst layer disposed thereon that is part of a 3D device disposed on orbeing fabricated on the substrate, the method comprising: disposing asubstrate atop a substrate support disposed in a lower processing volumeof a process chamber beneath an ion shield having a bias power appliedthereto, wherein the ion shield comprises a substantially flat membersupported parallel to the substrate support, and a plurality ofapertures formed through the flat member, and wherein the ratio of thediameter of the apertures to the thickness of the flat member has arange of about 10:1 to about 1:10; flowing a process gas into an upperprocessing volume above the ion shield; forming a plasma from theprocess gas within the upper processing volume; treating the first layerwith neutral radicals that pass through the ion shield; and heating thesubstrate to a temperature of up to about 550 degrees Celsius whiletreating the first layer.
 2. The method of claim 1, wherein the processgas comprises a nitrogen containing process gas.
 3. The method of claim2, wherein the nitrogen-containing process gas is ammonia (NH₃).
 4. Themethod of claim 3, wherein the process gas consists essentially ofammonia (NH₃) and an inert gas.
 5. The method of claim 4, wherein theprocess gas includes about 1 to about 99 percent ammonia (NH₃), whereinabout 50 to about 3000 watts of RF power is provided to form the plasmaof the process gas, and wherein the process chamber is maintained at apressure of about 2 to about 200 mTorr while treating the first layer.6. The method of claim 1, wherein the plasma is formed by providingabout 50 to about 3000 watts of RF power.
 7. The method of claim 1,further comprising: maintaining the processing volume at a pressure ofabout 2 to about 200 mTorr while treating the first layer.
 8. The methodof claim 1, further comprising: applying the bias power at about 10 toabout 2000 V DC or about 10 to about 2000 W of RF power to bias the ionshield.
 9. The method of claim 1, wherein the ratio of the diameter ofthe apertures to the thickness of the one or more substantially flatmembers is about 2:1 to about 1:2.
 10. The method of claim 1, whereinthe first layer is a high-k dielectric layer, a metal nitride film, or ametal oxide film.
 11. The method of claim 10, wherein the first layer isa hafnium-containing layer.
 12. The method of claim 10, wherein thefirst layer is a stack of layers comprising a hafnium oxide layer (HfO₂)disposed atop a silicon dioxide layer (SiO₂).
 13. The method of claim 1,wherein the process gas comprises an oxygen containing process gas, andwherein treating the first layer comprises oxidizing the first layer.14. The method of claim 1, wherein the process gas comprises at leastone of oxygen gas (O₂), ozone (O₃), or water (H₂O) vapor.